156 lines
7.2 KiB
Plaintext
156 lines
7.2 KiB
Plaintext
# Human settlement
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;; This rule set attempts to model human settlement in a landscape. It models
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;; western European pre-history moderately well. Settlement first occurs as
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;; nomadic camps on coastal promentaries (cells with four or more neighbours
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;; that are water). This represents 'kitchen-midden' mesolithic settlement.
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;;
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;; As grassland becomes available near camps, pastoralists appear, and will
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;; follow their herds inland. When pastoralists have available fertile land,
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;; they will till the soil and plant crops, and in doing so will establish
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;; permanent settlements; this is approximately a neolithic stage.
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;;
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;; Where soil is fertile, settlements will cluster, and markets will appear.
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;; where there is sufficient settlement, the markets become permanent, and you
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;; have the appearance of towns. This takes us roughly into the bronze age.
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;;
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;; This is quite a complex ruleset, and runs quite slowly. However, it does
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;; model some significant things. Soil gains in fertility under woodland; deep
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;; loams and podzols build up over substantial time. Agriculture depletes
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;; fertility. So if forest has become well established before human settlement
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;; begins, a higher population (more crops) will eventually be sustainable,
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;; whereas if human population starts early the deep fertile soils will not
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;; establish and you will have more pastoralism, supporting fewer permanent
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;; settlements.
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;; hack to speed up processing on the 'great britain and ireland' map
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if state is water then state should be water
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;; nomads make their first significant camp near water because of fish and
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;; shellfish (kitchen-midden people)
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if state is in grassland or heath and more than 3 neighbours are water and generation is more than 20 then state should be camp
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;; sooner or later nomads learn to keep flocks
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if state is in grassland or heath and some neighbours are camp then 1 chance in 2 state should be pasture
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;; and more herds support more people
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if state is in grassland or heath and more than 2 neighbours are pasture then 1 chance in 3 state should be camp
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if state is pasture and more than 3 neighbours are pasture and fewer than 1 neighbours are camp and fewer than 1 neighbours within 2 are house then state should be camp
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;; the idea of agriculture spreads
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if state is in grassland or heath and some neighbours within 2 are house then state should be pasture
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;; nomads don't move on while the have crops growing. That would be silly!
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if state is camp and some neighbours are ploughland then state should be camp
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;; Impoverished pasture can't be grazed permanently
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if state is pasture and fertility is less than 2 then 1 chance in 3 state should be heath
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;; nomads move on
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if state is camp then 1 chance in 5 state should be waste
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;; pasture that's too far from a house or camp will be abandoned
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if state is pasture and fewer than 1 neighbours within 3 are house and fewer than 1 neighbours within 2 are camp then state should be heath
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;; markets spring up near settlements
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if state is in grassland or pasture and more than 1 neighbours are house then 1 chance in 10 state should be market
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;; good fertile pasture close to settlement will be ploughed for crops
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if state is pasture and fertility is more than 10 and altitude is less than 100 and some neighbours are camp or some neighbours are house then state should be ploughland
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if state is ploughland then state should be crop
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;; after the crop is harvested, the land is allowed to lie fallow. But cropping
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;; depletes fertility.
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if state is crop then state should be grassland and fertility should be fertility - 1
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;; if there's reliable food available, nomads build permanent settlements
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if state is in camp or abandoned and some neighbours are crop then state should be house
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if state is abandoned and some neighbours are pasture then state should be house
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;; people camp near to markets
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if state is in waste or grassland and some neighbours are market then state should be camp
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;; a market in a settlement survives
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if state is market and some neighbours are inn then state should be market
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if state is market then state should be grassland
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;; a house near a market in a settlement will become an inn
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if state is house and some neighbours are market and more than 1 neighbours are house then 1 chance in 5 state should be inn
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;; but it will need some local custom to survive
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if state is inn and fewer than 3 neighbours are house then state should be house
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;; if there aren't enough resources houses should be abandoned
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;; resources from fishing
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if state is house and more than 2 neighbours are water then state should be house
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;; from farming
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if state is house and some neighbours are pasture then state should be house
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if state is house and some neighbours are ploughland then state should be house
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if state is house and some neighbours are crop then state should be house
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;; from the market
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if state is house and some neighbours are market then state should be house
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if state is house then 1 chance in 2 state should be abandoned
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if state is abandoned then 1 chance in 5 state should be waste
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## Vegetation rules
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;; rules which populate the world with plants
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;; Occasionally, passing birds plant tree seeds into grassland
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if state is grassland then 1 chance in 10 state should be heath
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;; heath below the treeline grows gradually into forest
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if state is heath and altitude is less than 120 then state should be scrub
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if state is scrub then 1 chance in 5 state should be forest
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;; Forest on fertile land grows to climax
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if state is forest and fertility is more than 5 and altitude is less than 70 then state should be climax
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;; Climax forest occasionally catches fire (e.g. lightning strikes)
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if state is climax then 1 chance in 500 state should be fire
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;; Forest neighbouring fires is likely to catch fire. So are buildings.
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if state is in forest or climax or camp or house or inn and some neighbours are fire then 1 chance in 3 state should be fire
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;; Climax forest near to settlement may be cleared for timber
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if state is in climax and more than 3 neighbours within 2 are house then state should be scrub
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;; After fire we get waste
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if state is fire then state should be waste
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;; waste near settlement that is fertile becomes ploughland
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if state is waste and fertility is more than 10 and some neighbours are house or some neighbours are camp then state should be ploughland
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;; And after waste we get pioneer species; if there's a woodland seed
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;; source, it's going to be heath, otherwise grassland.
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if state is waste and some neighbours are scrub then state should be heath
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if state is waste and some neighbours are forest then state should be heath
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if state is waste and some neighbours are climax then state should be heath
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if state is waste then state should be grassland
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## Potential blockers
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;; Forest increases soil fertility.
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if state is in forest or climax then fertility should be fertility + 1
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## Initialisation rules
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;; Rules which deal with state 'new' will waste less time if they're near the
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;; end of the file
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;; below the waterline we have water.
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if state is new and altitude is less than 10 then state should be water
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;; above the snowline we have snow.
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if state is new and altitude is more than 200 then state should be snow
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;; otherwise, we have grassland.
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if state is new then state should be grassland
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